Method of identifying when to initiate control sequences

ABSTRACT

A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Various applications require a nearly constant supply of reliableelectrical power to operate effectively. For example, hospitals mayrequire a constant and reliable supply of electricity to ensure medicalequipment in operating rooms and the like function when needed. Further,food retailers such as supermarkets and grocery stores may require aconstant and reliable supply of electricity to properly operaterefrigeration systems associated with display cases and freezers toprevent food spoilage.

While utility companies generally provide electrical power consistentlyand reliably, such power is sometimes interrupted due to inclementweather, unforeseen accidents, or maintenance. Electrical powerconsumers seeking to mitigate or avoid even minor interruptions in theirpower supply often rely on generators and other backup systems to supplyelectrical power during periods when electrical service from a utilitycompany is interrupted. Transfer switches enable these consumers toswitch between a primary electrical source (e.g., from a utilitycompany) and a secondary electrical source (e.g., a generator or otherbackup system) when one source becomes unreliable or requiresmaintenance.

SUMMARY

According to aspects of the disclosure, a method and system are providedfor transferring a load between a primary power source and a secondarypower source. In accordance with the disclosure, a controller senses,via a sensor, an electrical signal providing power from the primarypower source to the load. The controller detects a non-conforming powercondition or event. For example, such a non-conforming condition orevent may be related to an under or over voltage event, an under or overcurrent event, an harmonic content related event, a power (kW) relatedevent, a voltage or current balance related event, a k factor relatedevent, a crest related event and/or other similar power relatedparameters.

In one preferred arrangement, the controller detects the non-conformingpower event by determining that a parameter of the electrical signal isless than or greater than a first threshold value and, responsive to thedetection of the non-conforming power event, the controller determines aquantity of non-conforming power events that occur during a first timeinterval. The controller further compares the determined quantity ofnon-conforming power events to a second threshold value. Responsive tothe determined quantity of non-conforming power events being greaterthan the second threshold value, the controller may generate a generalcontrol signal. As just one example, such a control signal may initiatea control sequence to transfer the load from the primary power source toa secondary power source. Alternatively, the controller may initiate acontrol sequence to transfer the load from a secondary power source to aprimary power source.

The foregoing and additional aspects and implementations of the presentdisclosure will be apparent to those of ordinary skill in the art inview of the detailed description of various embodiments and/or aspects,which is made with reference to the drawings, a brief description ofwhich is provided next.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an automatic transfer switch according toan example of the disclosure.

FIG. 2 is a graph depicting a detection of an instability conditionaccording to an example of the disclosure.

FIG. 3 is a graph depicting a detection of a non-conforming power eventor condition according to another example of the disclosure.

FIG. 4 is a flow chart depicting example operations in accordance withthe disclosure.

FIG. 5 is another flow chart depicting example operations in accordancewith the disclosure.

While the present disclosure is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. Itshould be understood, however, that the present disclosure is notintended to be limited to the particular forms disclosed. Rather, theinvention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION I. Overview

Conventional transfer switches may detect a power outage condition for aprimary power source and then responsively transfer a load from theprimary power source to a secondary power source. Such conventionaltransfer switches may not be able to detect other types of conditions,which indicate that the primary power source is currently or mayimminently experience an outage or other problem. The automatic transferswitches of the present disclosure can advantageously detect and/orpredict instability in the power provided by the primary power sourceand then responsively transfer the load from the primary power source tothe secondary power source. This may, among other things, beneficiallyfacilitate automatically switching to a secondary power source beforethe primary power source experiences an outage.

II. Example System

Referring now to FIG. 1, a block diagram of an automatic transfer switch100 is depicted. The transfer switch 100 selectively couples a load 110to either a primary power source 112 or a secondary power source 114. Inan example, the primary power source 112 can be provided by a powerutility (e.g., via the electric grid) and the secondary power source 114can be provided by a backup generator. In other examples, the primarypower source 112 and/or the secondary power source 114 can be othertypes of power supplies (e.g., a battery). For instance, in analternative example, the primary power source 112 can be a renewableenergy power generation system (e.g., a wind power system, ahydro-electric power generation system, a solar power generation system,etc.), which is onsite at the load 110, and the secondary power source114 can be a power utility.

As shown in FIG. 1, the primary power source 112 is coupled to thetransfer switch system 100 via a primary conductor 116A, the secondarypower source 114 is coupled to the transfer switch system 100 via asecondary conductor 116B, and the transfer switch system 100 is coupledto the load 110 via an output conductor 116C. In general, the primarypower source 112 and the secondary power source 114 can provide electricpower in the form of an electric signal. In particular, for example, theelectric signal can be an alternating current (AC) voltage signal.

While the power sources 112, 114, the conductors 116A-116C, and the load110 are shown as a single-phase system in FIG. 1, other configurationscan be utilized in other examples. For instance, the power sources 112,114, the conductors 116A-116C, and/or the load 110 can be configured asa three-phase or another poly-phase system in other examples. In asingle-phase system, the conductors 116A-116C carry a single electricsignal. In a three-phase system, three conductors 116A-116C may eachinclude multiple conductors to facilitate carrying three separateelectric signals of the same frequency at different phases.

As also shown in FIG. 1, the transfer switch system 100 includes aswitch 118, which selectively connects the primary source 112 or thesecondary power source 114 to the load 110. The switch 118 may thusinclude one or more electrical devices. For example, such additionalelectrical devices may comprise one or more electromechanicalcontactors, solid state devices, circuit breaker devices, and/or othersuitable devices for electric power transfer. In one example, the switch118 includes a solenoid that activates an electrical contact to movebetween a connection to the primary conductor 116A and a connection tothe secondary conductor 116B. Other examples are also possible. Forexamples, such electrical devices may be internal or external to thetransfer switch system 100.

In practice, the switch 118 can be operably switched between multiplestates. In a first state, the switch 118 can connect the primary powersource 112 to the load 110. In a second state, the switch 118 canconnect the secondary power source 114 to the load 110.

The switch 118 is selectively switched between the first state and thesecond state under control of a controller 120. The controller 120 maythus provide control signals to the switch 118, which selectivelycontrol the state of the switch 118 to connect either the primary powersource 112 or the secondary power source 114 to the load 110. Thecontroller 120 controls the switch 118 based on an analysis of theelectric signal transmitted on the primary conductor 116A from theprimary power source 112 to the load 110. In particular, the controller120 monitors the electric signal on the primary conductor 116A forcertain conditions, which indicate that it may be beneficial to switchthe load 110 from the primary power source 112 to the secondary powersource 114 (e.g., an outage of the primary source 112 has or is likelyto occur).

To monitor the electric signal on the primary conductor 116A, thecontroller 120 is coupled to the primary conductor 116A via a firstsensor 122. The first sensor 122 may be internal (i.e., integral) orexternal to the controller 120. The sensor 122 senses the electricsignal transmitted on the primary conductor 116A and provides anindication of one or more parameters of the electric signal (e.g., amagnitude of current, voltage, power, etc.) to the controller 120.Similarly, to monitor the electric signal in the secondary conductor116B, the controller 120 may be coupled to the secondary conductor 116Bvia a second sensor. The second sensor may be similar in constructionand/or function to the first sensor 122. For example, the second sensormay be internal (i.e., integral) or external to the controller 120.Various different types of sensors may be utilized. In one example, thefirst sensor 122 can include a current transformer coupled to theprimary conductor 116A. In such an example, as current flows through theprimary conductor 116A, the current transformer induces a current in thesensor 122 that is proportional to the current flowing through theprimary conductor 116A. The sensor 122 and/or the controller 120 maythen determine from the induced current a voltage or current of theelectric signal transmitted on the primary conductor 116A from theprimary power source 112 to the load 110. Other examples are alsopossible.

The controller 120 can be, for example, a microcontroller, amicroprocessor, an application specific integrated circuit (ASIC)device, field programmable gate array (FPGA), programmable logiccontroller (PLC) or the like. In FIG. 1, the controller 120 is furthercoupled to a memory 124. The memory 124 can store any data required bythe controller 120 for detecting conditions of the primary power source112, initiating a power transfer, or executing any other functionality.For example, the memory 124 can store one or more threshold values 126,130, one or more time intervals 128, 132, application code (e.g., mainfunctionality firmware), initialization parameters, boot code, code forexecuting algorithms, code for determining a non-conforming power and/orinstability condition, code for setting user defined thresholds foralgorithms, check sums to determine whether code is corrupted, lockcodes, and/or other data. This data can be stored in the memory 124 atthe factory, manually entered via an input/output device (not shown), orremotely downloaded via the input/output device. The memory 124 can beintegrated with the controller 120, or the memory 124 can be externaland remotely coupled to the controller 120. The memory 124 can be, forexample, random access memory (RAM), read only memory (ROM), electronicerasable programmable read only memory (EEPROM), flash memory, or othervolatile or non-volatile memory (i.e., non-transitory computer readablemedia).

III. Example Operations

In line with the discussion above, the controller 120 monitors theelectric signal on the primary conductor 116A for certain conditions,which indicate that it may be beneficial to switch the load 110 from theprimary power source 112 to the secondary power source 114. Thecontroller 120 is configured or programmed to detect such conditionsusing the electric signal sensed by the sensor 122 and perhaps datastored in the memory 124 as inputs. For simplicity, operation of thecontroller 120 is described below in the context of the sensor 122sensing a voltage of the electric signal (i.e., a voltage signal) on theprimary conductor 116A; however, the sensor 122 can additionally oralternatively sense a current or another parameter of the electricsignal on the primary conductor 122 as an input for condition detection.

In one aspect, the controller 120 monitors the voltage signal on theprimary conductor 116A to detect an instability condition and/or anon-conforming power event. For example, in one exemplary arrangement,the instability condition may be characterized by relatively rapidfluctuations in the voltage signal and may indicate that the primarypower source 112 may imminently experience a power outage. Thecontroller 120 may detect the instability condition by detecting whenmore than a threshold number of fluctuations occur within apredetermined time interval.

In one example, the controller 120 monitors the voltage signal to detectnon-conforming power events as previously described herein. As just oneexample, such non-conforming power condition or event may be a momentarypower outage or power dip in which the voltage signal drops below afirst threshold value 126 (which may be stored in the memory 124). Insome implementations, the controller 120 may detect a non-conformingpower event by detecting each time the voltage drops below the firstthreshold value 126. In other implementations, the controller 120 maydetect a non-conforming power event by detecting each time the voltagedrops below and then returns above the first threshold value 126.

When the controller 120 detects a non-conforming power event, thecontroller 120 initiates a timer. The timer begins to count a period oftime equal to a first time interval 128 (which also may be stored in thememory 124). While the timer counts to the first time interval 128, thecontroller 120 continues to monitor the voltage signal and count eachtime another non-conforming power event occurs. The controller 120compares the quantity of non-conforming power events detected to asecond threshold value 130 to determine whether a threshold number ofnon-conforming power events have occurred during the first time interval128.

If, at any time during the first time interval 128, the controller 120determines that the quantity of non-conforming power events detected isgreater than the second threshold value 130, the controller 120 (i)determines that an instability condition exists and (ii) initiates acontrol sequence to switch the load 110 from the primary power source112 to the secondary power source 114. The control sequence can involvethe controller 120 providing a control signal to the switch 118 to causethe switch 118 to change from the first state to the second state.Additionally or alternatively, the control sequence can involve thecontroller 120 providing a control signal to the secondary power source114 to cause the secondary power source 114 to prepare for providingpower to the load 110. For instance, responsive to the control signalfrom the controller 120, the secondary power source 114 can power on,startup, and/or switch from an idle mode to an active mode, among otherpossibilities.

Whereas, if the controller 120 determines that the quantity ofnon-conforming power events is less than the second threshold value 130at the end of the first time interval 128, then the controller 120 can(i) determine that no instability condition exists, (ii) reset thetimer, and/or (iii) maintain the switch 118 in the first state.

FIG. 2 is a graph illustrating a voltage signal 134 exhibiting aninstability condition, which can be detected by the controller 120 asdescribed above. As shown in FIG. 2, the voltage signal 134 initiallydrops below the first threshold value 126 at a time t₁. Responsive tothe controller 120 detecting this initial voltage signal 134 drop belowthe first threshold value 126 at time t₁, the controller 120 initiates atimer that then counts up to the first time interval 128. In the exampleshown in FIG. 2, the timer reaches the first time interval 128 at a timet₃.

Also, responsive to the controller 120 detecting the initial voltagesignal drop below the first threshold value 126 at time t₁, thecontroller 120 initiates a counter for counting non-conforming powerevents via timer 136 (e.g., by setting the counter to an initial valuesuch as 1). Timer 136 comprises another timer that may be used todetermine the duration of what should be considered a monitorednon-conforming power event. For example, if timer 136 is set to 1.0seconds, then a voltage drop below the threshold for 0.5 seconds wouldnot be categorized as a monitored event. However, if the voltage were todrop below the threshold for a duration of 1.5 seconds, such a durationwould then be categorized as a monitored event. As such, the timer 136may be used as a filter to avoid nuisance trips and used to count onlyevents of a predetermined significant enough magnitude. Again, suchfilter parameters can be tailored to the specific transfer switchapplication.

Preferably, the timer 128 comprises a rolling timer. For example, such arolling timer may be able to identify a grouping of events (i.e., aquantity defined by a threshold) that fall within the first timeinterval 128. Although in certain situations an application may not meetthe threshold value 130 number of events that are required within thetime interval 128=t3−t1 as shown in FIG. 2, and the control process maystill be initiated. As just one example, referring to FIG. 2, assumethat a large gap were to be present between the first event 136 and thethird event 136 to fall outside the first time interval 128. In such asituation, if a fourth event were to occur in close proximity to thethird event 136, then the second, the third and the fourth event wouldfall within a timer period equal to or less than the time set in thefirst time interval 128 which would still initiate a control sequence.

While the timer progresses to the first time interval 128, thecontroller 120 continues to monitor the voltage signal 134 to detect andcount the occurrence of additional non-conforming power events 136(e.g., a number of times the voltage signal 134 returns above the firstthreshold value 126 and then drops below the first threshold value 126again). Each time the controller 120 detects a non-conforming powerevent 136, the controller 120 increments the counter. The controller 120continues in this manner until either the controller 120 determines thatthe number of non-conforming power events 136 indicated by the counterexceeds the second threshold value 130 or the timer reaches the firsttime interval 128 (e.g., at time t₃).

In this example, the second threshold value 130 is two non-conformingpower events. Accordingly, as indicated in FIG. 2, the controller 120determines that an instability condition exists at a time t₂ based on adetermination that three non-conforming power events 136 have occurredwithin the first time interval 128 at time t₂. Accordingly, at time t₂,the controller 120 initiates a control sequence to switch the load 110from the primary power source 112 to the secondary power source 114 asdescribed above.

In another aspect, the controller 120 monitors the voltage signal on theprimary conductor 116A to detect a non-conforming power condition. Thenon-conforming power condition may be characterized by the primary powersource 112 providing threshold low (or possibly zero) voltage on theprimary conductor 116A for at least a predetermined amount of time. Thismay, for example, help to mitigate power continuity issues when a poweroutage has occurred on the primary power source 112.

In one example, to detect a non-conforming power condition, thecontroller 120 monitors the voltage signal to detect when the voltagesignal drops below the first threshold value 126 (stored in the memory124). Thus, in this example, the threshold value used to detect thenon-conforming power condition is the same as the threshold value usedto detect an instability condition as described above; however, inalternative examples, the threshold value used to detect thenon-conforming power condition can be different than the threshold valueused to detect the instability condition.

When the controller 120 detects that the voltage signal drops below thefirst threshold value 126, the controller 120 then determines whetherthe voltage signal remains below the first threshold value 126 for asecond time interval 132 (which may be stored in memory 124). Forexample, responsive to the controller 120 detecting that the voltagesignal dropped below the first threshold value 126, the controller 120may initiate a timer. The timer begins to count a period of time equalto a second time interval 132. If the controller 120 determines that thevoltage signal returns to a level above the first threshold level 126before the timer reaches the second time interval 132, the controller120 (i) determines that no non-conforming power condition exists, (ii)resets the timer, and (iii) maintains the switch 118 in the first state.As a result, the load 110 continues to receive power from the primarypower source 112.

Whereas, if the controller 120 determines that the voltage signalremains below the first threshold 126 for the entire second timeinterval 132, then the controller 120 determines that a non-conformingpower condition exists. Responsive to determining that a non-conformingpower condition exists, the controller 120 initiates the controlsequence to switch the load 110 from the primary power source 112 to thesecondary power source 114. As described above, the control sequence caninvolve the controller 120 providing control signals to the switch 118and/or the secondary power source 114.

FIG. 3 is a graph illustrating a voltage signal 134 exhibiting anon-conforming power condition, which can be detected by the controller120 as described above. As shown in FIG. 3, the voltage signal 134 dropsbelow the first threshold value 126 at a time t₁. Responsive to thecontroller 120 detecting this voltage signal drop below the firstthreshold value 126 at time t₁, the controller 120 initiates a timerthat then counts up to the second time interval 132. In the exampleshown in FIG. 3, the timer reaches the second time interval 132 at atime t₂.

While the timer counts to the second time interval 132, the controller120 continues to monitor the voltage signal 134 to determine whether thevoltage signal 134 returns to a level above the first threshold value126. At time t₂, the controller 120 determines that the voltage signal134 has remained below the first threshold value 126 for the entiresecond time interval 132. Accordingly, at time t₂, the controller 120determines that a low power condition exists and responsively initiatesa control sequence to switch the load 110 from the primary power source112 to the secondary power source 114 as described above. Preferably, ifat any time during this time interval, the voltage signal 134 risesabove the threshold 126, the timer will reset since the voltage signal134 must remain below the threshold 126 for the entire time interval132.

According to aspects of the present disclosure, the automatic transferswitch can be operable to detect an instability condition, anon-conforming power condition, or both instability and non-conformingpower conditions. Detecting both instability conditions andnon-conforming power conditions may provide for more robust protectionagainst power interruptions (or non-conforming power) at the load 110.Notably, the methods for detecting non-conforming power conditionsdescribed above generally cannot detect an instability condition as thefluctuations characteristic of the instability condition are generallytoo brief to be considered a non-conforming power condition (e.g., inwhich an outage has occurred). However, the methods for detectinginstability conditions may beneficially facilitate the controller 120predicting that a non-conforming power condition is about to occur (orother non-conforming power condition) and thereby allow the automatictransfer switch 100 to take precautionary measures (potentially prior toa loss of primary power actually occurring).

FIG. 4 is next a flow chart depicting an example set of operations thatcan be carried out in an implementation of a process in accordance withaspects of the present disclosure. As shown in block 50, the methodbegins with a controller sensing, via a sensor, an electrical signalproviding power from the primary power source to the load. At block 52,the controller detects a non-conforming power event (i.e., designated asa power event) by determining that a parameter of the electrical signalis less than a first threshold value. At block 54, responsive to thedetection of the non-conforming power event, the controller determines aquantity of non-conforming power events that occur during a firstpredetermined time interval. At block 56, the controller compares thedetermined quantity of non-conforming power events to a second thresholdvalue. At block 58, responsive to the determined quantity ofnon-conforming power events being greater than the second thresholdvalue, the controller initiates a control sequence to transfer the loadfrom the primary power source to a secondary power source.

FIG. 5 is a flow chart depicting another example set of operations thatcan be carried out in an implementation of a process in accordance withaspects of the present disclosure. As shown in block 70, the methodbegins with a controller sensing, via a sensor, an electrical signalproviding power from the primary power source to the load. At block 72,the controller detects a non-conforming power event (i.e., designated asa power event) by determining that a parameter of the electrical signalis less than a first threshold value. At block 74, responsive to thedetection of the non-conforming power event, the controller determines aquantity of non-conforming power events that occur during a firstpredetermined time interval. At block 76, the controller compares thedetermined quantity of non-conforming power events to a second thresholdvalue. At block 78, responsive to the determined quantity ofnon-conforming power events being greater than the second thresholdvalue, the controller initiates a control sequence to transfer the loadfrom the primary power source to a secondary power source.

At block 80, responsive to detecting the non-conforming power event, thecontroller waits a second predetermined time interval. At block 82,after waiting the second predetermined time interval, the controllerdetermines that the parameter of the electrical signal is less than thefirst threshold value. At block 84, responsive to determining that theparameter of the electrical signal is less than the first thresholdvalue after waiting the second predetermined time interval, thecontroller transfers the load from the primary power source to thesecondary power source.

IV. Example Variations

As described above, the controller 120 can detect an instabilitycondition exists when a threshold number of fluctuations relative to thefirst threshold value occur within the first time interval. In someimplementations, the instability condition can indicate that the primarypower source is currently unstable. Additionally or alternatively, theinstability condition can indicate that the primary source is likely tobecome unstable (i.e., the instability condition can be predictive ofthe primary power source becoming unstable).

As described above, the instability condition and the non-conformingpower condition may be detected by determining when a parameter of theelectric signal drops below the first threshold value. In additional oralternative implementations, the first threshold value can be a range ofvalues such that the instability condition and the non-conforming powercondition are detected based on a determination of when the parameter ofthe electric signals is outside the range of values (e.g., drops below alower boundary or rises above an upper boundary).

According to aspects of the present disclosure, the switch 118 can beconfigured as an open transfer switch, a delayed transfer switch, aclosed transfer switch, an electromechanical transfer switch, a solidstate transfer switch, a soft start transfer switch, and/or a statictransfer switch. Additionally, although the switch 118 is describe aboveas having a first state in which the switch 118 connects the primarypower source 112 to the load 110 and a second state in which the switch118 connects the secondary power source 114 to the load 110, the switch118 may have a third state in which neither the primary power source 112nor the secondary power source 114 are connected to the load 110 inadditional or alternative implementations.

According to further aspects of the present disclosure, the thresholdvalues and/or the time intervals can be predetermined values stored inmemory at the time of manufacture and/or based on user input aftermanufacture. In general, however, the threshold values and the timeintervals may be predetermined in the sense that they are set prior tothe controller analyzing the electrical signal on the primary conductor.Alternatively, or in addition to such predetermined values, intelligentor automatic self programming of such settings may also be utilized. Forexample, the controller may be configured to monitor the signal for apredetermined period of time. Based on the quality and/or stability ofits power during this monitored period of time, the controller may beconfigured to use a programmed algorithm to adjust the duration, timers,and/or thresholds of its own settings to adjust higher or lowersensitivities. One advantage of such a smart or intelligent controlleris that it would allow the controller to self configure to optimalsettings that might be unique to the specific transfer switchapplication (e.g., such as a hospital, a supermarket, a data center,etc.) and therefore reduce nuisance trips or missing certain events.

While particular implementations and applications of the presentdisclosure have been illustrated and described, it is to be understoodthat the present disclosure is not limited to the precise constructionand compositions disclosed herein and that various modifications,changes, and variations can be apparent from the foregoing descriptionswithout departing from the spirit and scope of the invention as definedin the appended claims.

What is claimed is:
 1. A method for initiating a transfer of a load between a primary power source and a secondary power source, the method comprising: sensing an electrical signal providing power from the primary power source to the load; detecting a non-conforming power event by determining that a parameter of the electrical signal is greater than a first threshold value; responsive to detecting the non-conforming power event, determining a quantity of non-conforming power events that occur during a first time interval; comparing the determined quantity of non-conforming power events to a second threshold value; and responsive to the determined quantity of non-conforming power events being greater than the second threshold value, generating a control signal.
 2. The method of claim 1 further comprising initiating a transfer of the load.
 3. The method of claim 1 further comprising transferring the load from the primary power source to the secondary power source.
 4. The method of claim 1 further comprising: responsive to detecting the non-conforming power event, waiting a second time interval; and after waiting the second time interval, determining that the parameter of the electrical signal is less than the first threshold value.
 5. The method of claim 4, further comprising: responsive to determining that the parameter of the electrical signal is less than the first threshold value after waiting the second time interval, transferring the load from the primary power source to the secondary power source.
 6. The method of claim 1, wherein the parameter is a voltage of the electrical signal.
 7. The method of claim 1 wherein the first threshold value comprises a predetermined value.
 8. The method of claim 1 wherein the first time interval comprises a predetermined time interval.
 9. The method of claim 1 wherein the first threshold value comprises an adjustable value.
 10. The method of claim 1 wherein the first time interval comprises an adjustable time interval.
 11. An apparatus for initiating a transfer of a load between a primary power source and a secondary power source, comprising: a processor; and a memory including computer program code which, when executed by the processor, causes the apparatus to: sense an electrical signal providing power from the primary power source to the load; detect a non-conforming power event by determining that a parameter of the electrical signal is greater than a first threshold value; responsive to detecting the non-conforming power event, determine a quantity of non-conforming power events that occur during a first time interval; compare the determined quantity of non-conforming power events to a second threshold value; and responsive to the determined quantity of non-conforming power events being greater than the second threshold value, generate a control signal.
 12. The apparatus of claim 11, wherein the memory includes program code, which when executed by the processor causes the apparatus to initiate a transfer of the load.
 13. The apparatus of claim 11, wherein the memory includes program code, which when executed by the processor causes the apparatus to transfer the load from the primary power source to the secondary power source.
 14. The apparatus of claim 11, wherein the memory includes program code, which when executed by the processor causes the apparatus to: responsive to detecting the non-conforming power event, wait a second time interval; and after waiting the second time interval, determine that the parameter of the electrical signal is less than the first threshold value.
 15. The apparatus of claim 14, wherein the memory includes program code, which when executed by the processor causes the apparatus to: responsive to determining that the parameter of the electrical signal is less than the first threshold value after waiting the second time interval, transfer the load from the primary power source to the secondary power source.
 16. The apparatus of claim 11, wherein the parameter is a voltage of the electrical signal.
 17. The apparatus of claim 11 wherein the first threshold value comprises a predetermined value.
 18. The apparatus of claim 11 wherein the first threshold value comprises an adjustable value.
 19. The apparatus of claim 11 wherein the first time interval comprises one of a predetermined time interval or an adjustable time interval.
 20. A computer program product comprising a non-transitory computer readable medium having computer readable code stored thereon, which when executed by a processor, causes an apparatus to perform: sensing an electrical signal providing power from a primary power source to a load; detecting a non-conforming power event by determining that a parameter of the electrical signal is greater than a first threshold value; responsive to detecting the non-conforming power event, determining a quantity of non-conforming power events that occur during a first time interval; comparing the determined quantity of non-conforming power events to a second threshold value; and responsive to the determined quantity of non-conforming power events being greater than the second threshold value, generating a control signal. 